Hierarchy classification:

1. top of the aat hierarchies
2. Brand Names Facet
3. Brand Names (hierarchy name)
4. brand name materials

Anotations

Scope note:

Registered trademark for foamed polystyrene that was developed in the 1940s. Polystyrene expanded into a multicellular mass that has one-sixth the weight of cork and will withstand temperatures above 170 degrees Fahrenheit.